The present locking assembly provides security for enclosures such as grade level boxes used to contain cable TV equipment, data transmission lines, telephone switching equipment, service lines, power transmission devices, and water meters, for example. The invention also has application to other types of ground level enclosures and similar enclosures generally. A significant aspect of the invention is that the locking assembly is self-latching when the lid for the enclosure is simply placed atop the enclosure and forced downwardly to a locked position by applying foot pressure only to the top of the lid. Hence, any need for special tools to lock the lid is avoided.